Gas-operated actuating mechanism for firearms



F. 1.. HuMEs'roN 2,340,962 GAs-oPERATED ACTQATING-MECHANISMS Fori FIREAMs Filed March 9, 1942 2 Sheets-Sheet l T @M P G7/7. Jv /m/ mw W, 1%. /L Z W 6 f// M w /7 f /Mjw .S ,M n? E m a wm. :un .Inu In Mmm u n r :HH ay xn m .d u n.

Feb. 8, 1944.

Patented Feb. 8, 1944 UNITE lST rss ` T' oFFiCE GAS-OPERATED ACTUATING MECHANISM FOR FIREARMS I Application March 9, 1942, Serial No. 433,907

1 Claim.

The present invention relates to improvements in self-loading repeating firearms and relates more particularly to a construction and arrangement of parts whereby energy derived from the discharge of a cartridge is caused by gas pressure to actuate a piston and associated mechanism to effect the operation of the breech-bolt of the firearm.

One of the objects of the present invention is to provide a nrearm with superior gas-actuated operating-mechanism combining reliability of operation and lightness of weight.

Another object of the present invention is to provide in a self-loading rearm of the gas-perated type a superior construction and arrangement of parts whereby gas pressure emanating' from the bore of the barrel of the rearm may be directed outwardly in a substantially-radial direction to actuate a simple piston and then have the energy thus developed converted into motion lengthwise of the firearm to actuate the breech-bolt thereof.

AV further object of the present invention is to provide a gas-operated self-loading firearm with superior piston and associated means whereby it is not necessary to provide integral piston-chamber means.

With the above and other objects in View, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel overthe prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. l is a broken View partly in side elevation and partly in vertical central-longitudinal section of the central portion of a gas-operated selfloading firearm embodying one form of the present invention;

Fig. 2 is a broken view partly in side elevation and partly in vertical central-longitudinal section of the parts of the firearm immediately adjacent the piston thereof and shown 0n a larger scale than Fig. 1;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a similar View taken on the line 4 4 of Fig. 2;

Fig. 5 is a transverse sectional View taken on the line 5-5 of Fig. 2;

Fig. 6 is a broken longitudinal sectional view taken on the line 5 6 of Fig. 2; a

Fig. 7 is a broken perspective View of a portion of the barrel together with the mounting-yoke and piston-stud; f

Fig. 8 is a broken perspective view of the forward portion of the action-slide, detached;

Fig. 9 is a perspective view of the transmittinglever, detached; and

Fig. 10 is a perspective view oi the piston, detached.

`The particular gas-operated self-loading lirearm herein chosen for the purpose of illustrating one form of the present invention, includes in the main a stock I5, a barrel-cover I5, a receiver I1, trigger-plate unit I8 and barrel i9. The stock I5 and barrel-cover I6 are preferably formed of wood or other suitable heat-insulating material, while the receiver I1, trigger-plate `unit I8 and barrel I9 are preferably formed of high-grade steel to aord maximum strength and minimum weight. l

The rear end of the barrel I9 is rigidly attached inany approved manner to the forward end of the receiver I1 and the trigger-plate unit I8 is attached to the under part of the said receiver I1, as is especially well shown in Fig. l. The forward portion of the stock I5 underlies the barrel I9 and is hollowed out, as shown in Fig. 1, to provide a vertical longitudinal upwardly-opening recess for purposes as will hereinafter appear. The barrel-cover I6 extends over the upper portion of the barrel I9 in substantial accordance with usual practice in military iirearms.

A short distance forwardly of the front end of the receiver I1, the barrel I9 has rigidly attached to it, a mounting-yoke or -member 2l, the upper portion of whichlatter is formed with a cylindrically-contoured passage 22 in which snugly ts the adjacent portion of the barrel I9. Extending transversely through the mounting-yoke 2I about midway the height thereof, is an anchoring-pin 23, substantially the upper half of which extends through the lower portion of the barrel IS to lock the said mounting-yoke to the barrel, in a manner as is especially well shown in Figs. 2 and 4.

The lower portion oi the mounting-yoke 2| is bifurcated by forming the same with a downwardly-opening notch 24 to thus create two downwardly extending laterally spaced apart mounting-arms 25-25 forming the respective opposite sidewalls of the notch 24 just referred to.

Extending beneath the barrel I9 and through the notch 24 in the mounting-yoke 2I is the horizontal arm 2S of a transmitting-lever generally designated by the reference character 21. The said transmitting-lever 21 also includes a vertical 25, the transmitting-lever 27 is formed with anY upwardly-opening recess r30freizeit/ing the coni-A cally-contoured lower portion or a cup-shaped piston 3| mounted for reciprocation on an axis extending substantially perpendicular to the longitudinal axis of the barrel i9. The said piston' 3| is formed in its upper portion with an Aupwardly-opening cylindrically contoured recess 32 tting over with a close sliding nt, the guide-stem 33 of a piston-guide stud 34. The said stud 34' is formed with an externally-threaded upper por"- tion 35 of larger diameter than the guide-stem 33 and iirmly seated in an internally-threaded downwardly-opening socket 33 formed in the under portion of the barrel I3 just rearwardly of the mounting-yoke 2| thereon.

Owing-to the differences in diameter between the upper portion 35 of the stud 34 and its guidestem 33, the said stud is formed at the junction of the two said portions 33 and 53 with a downwardly-facing annular stop-shoulder 3l which is normally engaged by the upper edge of the cup-- shaped piston 3|.

Extending axially through the piston-guide stud 34 is a vertical gas-passage 33 communicating at its lower end with the recess 32 in the piston 3| and communicating at its upper end with a short vertical or radial gas-passage 33. The last-mentioned gas-passage 39 communicates, in turn, at its upper end with the bore it of the barrel i@ at a point in axial alignment with the vertical longitudinal axis of the piston-guide stud 34, as is especially well shown in Figs. 2 and 3. l f f The` vertical bifurcated arm 23 of the transmitting-lever 2l normally bears against the respective forward faces of the side-walls il-4| of la crosshead 42 constituting the integral forward portion of a reciprocating action-slide generally designated by the reference character 43. The said crosshead |32 includes a vertical rear wall 44 vand is of -substantially U-shaped'iorin in cross section at all points forwardly of its said rear wall 44 to thus provide a recess 45 which opens both upwardly and forwardly and which normally houses the lower portion of the mounting-yoke 2 the piston mechanism and the major portion of the transmitting-lever 21, as is especially well shown in Figs. l and 2.

In addition to its crosshead 42, the action-slide 43 above referred to includes a bar 46 formed integral with the crosshead 42 and extending rearwardly from the upper portion of the righthand side-wall 4| of the said crosshead in parallelism with the barrel I9. At the rear of its bar 46 the action-slide 43 `is formed with an outwardly-extending operating-handle 4l, and slightly forwardly of the said handle the actionslide is, formed with an upwardly-extending lug 48h The action-slide 43 may be operatively connected in any approved manner to a breech-bolt 43 of any lsuitable type which, in the particular iirearm chosen for illustration, is mounted in the receiver |'l with capacity for both-reciprocation and oscillation therein in a manner generally similar to the construction of the well-known Garand military rifle. The operating-connection between the action-slide 43 and the breech-bolt 49 is, in the instance shown, accomplished by providing the portion of the said action-slide in and adjacent its lug 48 with a cam-recess 50 receiving an operating-lug 5| laterally projecting from the forward end of the breech-bolt 49 such, for instance, in a manner as is more fully set forth in my co-pending application Serial No. 411,783, led September 22, 1941.

At a point immediately below the bar 4B, the cross-head 42 of the action-slide 43 is formed with a rearwardly-opening conical recess 52 receiving the'conical forward end of a reciprocating and horizontally-arranged breech-closing plungerl 53, as isespecially well shown in Fig. l. At its rear end lthe breech-closing plunger 53 is formed with a rearwardly-extending relativelyslender stem 54 tting within the forward end of ahelical breech-closing spring. At the junctionV of" the forward end of its stem 54 with itsl main portion, the plunger 53 is provided with a rearwardly-facing annular spring-seat 56 against which the forward end of the breech-closing spring 55 thrusts.'

The breech-closing spring 55 is mainly contained in a relatively-long forwardly-opening spring-receiving pocket 5l formed in the right side-wall; of the receiver |`I and extending in parallelism `with' thebreech-closing plunger 53, which latter telescopes into the said pocket in a manner as will hereinafter appear. The rear endo-f the breech-closing spring 55 seats against the closed rear end or the spring-receiving pocket 3l, "and the said spring exerts a constant but yielding effort to move the plunger 53 forwardly and'hence also tomove the action-slide 43 to the limit of its -forward movement, to therebyv cause the said action-slide to, in turn, move the breech-bolt '113` forwardly into its breech-closing position.

The action-slide 43 may be releasably attached lto the Firearm-structure in any suitable manner to effect its guidance in a path longitudinally of the rearm, such, for instance, as in the manner shown and described in my co-pending application above referred to.

'When' the firearm is discharged, gas pressure will be created in the bore 40 of the barrel 9, and in addition to propelling the projectile forwardly, the said pressure will exert itself downwardly through the gas-passage 39 in thev said barrel, thence through the gas-passage 38 in the piston-guide stud 34 to impinge against the vcupshaped piston 3| at the bottom of the upwardlyopening recess 32 therein.v

The impingement of the gas pressure upon the vertically-reciprocating piston 3| will eect the rapid downward movement thereof with the result that the transmitting-lever 2l will be rocked in a counterclockwise direction to thereby cause the vertical arm 28 thereof to propel the actionslide 43 rearwardly. Owing to the `connection between the said action-slide 43 and the breechbolt 49, the latter will also be propelled rearwardly.

The downward movement of the piston 3| and the counterclockwise rocking movement of the transmitting-lever 21 will be of relatively limitedl extent and far less than the required movement of the action-slide 43. The swinging movement of the transmitting-lever 21 will be checked by the engagement of the rear upper corner of its bifurcated vertical arm 28 with the forward face of the upper portion of the mounting-yoke 2l, as is indicated by broken lines in Fig. 2. The limiting of the counterclockwise turning movement of the transmitting-lever 27 as just described will, of course, in turn limit the downward movement of the piston 3l well before the latter can ride clear of the guide-stem 33 of the piston-guide stud 34.

Despite the short rearward swinging movement of the vertical arm 28 of the transmitting-lever 21, such a rapid movement will be imparted to the action-slide 43 thatthe same will very rapidly coast rearwardly against the tension of the breech-closing spring 5-5 and will effect the full retirement of the breech-bolt @-9 to thereby extract and eject the just-fired cartridge preparatory to the insertion of a fresh cartridge. When the action-slide 43 and the breech-bolt 49 have completed their required rearward movement, the breech-closing spring 55 will assert itself to restore the parts to the positions in which they are shown by full lines in Figs. l to 6 inclusive.

By means of a structure of the general character shown and described as one mode of carrying out the present invention, many advantages are secured, among which may be mentioned the lack of need for an integral bulky lug offsetting from the barrel of the firearm. Furthermore, by means of the present invention, the transmitting-lever 21 or other suitable translating device, may be utilized to limit the powerstroke of the piston.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claim are intended to be embraced therein.

I claim:

A gas-operated self-loading firearm-structure including in combination: a receiver; a breechbolt movable in the said rreceiver in a vdirection lengthwise of the firearm-structure; a barrel projecting forwardly from the said receiver and formed in its underside with a downwardly-opening internally-threaded stud-receiving recess communicating with the bore of the said barrel; a piston-guide stud threaded into the downwardly-opening recess of the said barrel and projecting downwardly therefrom and formed with a vertical gas-passage communicating with the recess in the said barrel; a cup-shaped piston mounted on the said piston-guide stud and movable downwardly thereon when the rearm is discharged; a bell-crank-shaped lever pivotally connected to the said barrel at a point mainly beneath the same and forwardly of the said piston and including a substantially-vertical arm bifurcated to form two upwardly-extending 1ingers respectively located on opposite sides of the said barrel and a substantially-horizontal arm extending rearwardly from its junction with the said vertical arm into position for the actuation of its rear end ina downward direction by the said cup-shaped piston; and an action-slide operatively interconnecting the substantially-vertical arm of the said bell-crank-shaped lever to the said breech-bolt to effect the rearward movement of the latter when the substantiallyhorizontal arm of the said lever is forced downwardly by the said piston, the said action-slide including at its forward end a cross-head having two side walls respectively located on opposite sides of the said barrel and respectively engaged by one of the two upwardly-extending lingers of the vertical arm of the said lever.

FREDERICK L. HUMESTON. 

